It is well known that the use of computer keyboards for extensive periods of time can cause office workers and others to develop posture- and stress-related injuries, including Carpal Tunnel Syndrome. Carpal Tunnel Syndrome generally results from stress to the wrist area caused by a combination of wrist posture and chronic repetitive wrist and finger motions. In response to this phenomena, wrist/arm supports have been developed that consist of an elongated pad, which typically is positioned along and adjacent to the front of the keyboard. Instead of a singular elongated pad, separate support pads for each wrist have also been employed. Prior art wrist rests help to relieve posture- and stress-related injuries of keyboard users by supporting the wrist in a position relative to the hand and arm so that the degree of bending at the wrist is decreased, thus decreasing the stress caused by repetitive motion.
While prior art wrist rests may be suitable for use with keyboards, they are not satisfactory when used with computer pointing devices. The popularity of several graphical user interfaces (GUIs) such as Microsoft Windows.TM., IBM OS/2.TM. and Apple System 7.TM. for use with personal computers has resulted in a dramatic increase in the utilization of computer pointing devices, and hence, related injuries. As an example, over 15 million copies of Microsoft Windows.TM. operating systems have been sold. It has been suggested that Microsoft Windows has had the strongest singular impact on the sale and use of pointing devices in recent years.
While making computers easier to use, the increased use of pointing devices has become a significant co-contributor to the widespread development of posture- and repetitive stress-related disorders. Such disorders typically develop in the neck, shoulders, and/or wrists. These disorders can impair comfort, health, and productivity to the point of being disabling. For more information on repetitive stress injuries, please see "The Handling of an Epidemic," published in Working Woman, February 1993, pp. 60-65, which is hereby incorporated by reference. For information on ergonomics in the workplace, see "Video Display Terminal Ergonomics," published in Professional Safety, June 1992, pp. 32-39, which is also incorporated by reference.
Computer pointing devices have evolved into several primary categories, including the computer mouse, trackballs, joysticks, pens, and additional keyboard keys. The specific advantages and disadvantages of each category vary relative to the intended use, design, and functionality of the pointing device. For example, pointing devices vary relative to their shape, ergonomics, and the employed means of converting tracking movement of the device to movement of a cursor on a computer screen. These characteristics determine the amount of space needed to use the pointing device, the intuitiveness of the device, as well as the time required to perform a pointing task, i.e., the quickness of target acquisition. Greater intuitiveness in directing a cursor motion via the manipulation of a pointing device decreases the time to achieve a comfortable skill level with an unfamiliar pointing device, and results in quicker target acquisition speed. In many cases and for many uses, once a user is comfortable with a pointing device, the speed of the cursor can be accelerated to increase the speed of cursor movement relative to hand movement. This adjustment is made by the user adjusting either the operating system software, through software that accompanies the pointing device, or through a separate software utility. In summary, the speed of target acquisition and the overall efficiency of a pointing device are dependent upon the intuitiveness of the device, the ergonomics of the device, and the relative cursor speed as set by software.
Of the above-described pointing devices, the computer mouse has become the most popular. Computer mice have the advantages of user familiarity and of allowing moderately quick target acquisition. However, there are a number of disadvantages associated with their use. For example, computer mice are usually positioned on a mouse pad or other level and flat surface next to the keyboard. This placement requires a considerable amount of dedicated desk space, which is a limited commodity in typically crowded workspace environments. As a further disadvantage, pointer control using a computer mouse often requires movement of the shoulder and arm, in addition to the wrist, hands and fingers. Furthermore, computer mice must often be lifted and repositioned on the mouse pad in order to properly position the pointer. These extra motions are fatiguing to the shoulder and neck areas and/or irritating to the user's wrist, and can further contribute to Carpal Tunnel Syndrome. Computer mice users tend to rest their wrists on a hard desk surface, the edge of the mouse pad, or the edge of a desk. Irrespective of the chosen resting position, the user's wrist typically rests on a surface that is irritating to the wrist and in a position such that the wrist is forced to bend, both of which are contributing factors to Carpal Tunnel Syndrome.
In comparison to computer mice, trackballs require less desk space and are easily incorporated into computer keyboards and portable computers, e.g., laptop or notebook computers. However, trackballs are typically considered to be less intuitive and more difficult to control than computer mice. Thus, trackballs have slower target acquisition than computer mice. Further, trackballs that are integral with or that attach to portable computers, i.e., miniature trackballs and ball-point mice, have traditionally been of a relatively small size, in order to increase portability and to conserve space around the keyboard. These small trackballs are even more awkward to use than standard trackballs, especially for habitual users of computer mice.
In U.S. Pat. No. 5,131,614 to Garcia et al., a wrist support for alleviating some of the posture- and stress-related problems associated with the use of computer mice is suggested. While it is unclear from the patent, an illustration of a probable construction and use of the Garcia et al. wrist support is shown herein with reference to FIGS. 1 and 2A-2D. A wrist support 20 suggested by Garcia et al. includes a longitudinal pad 22 and base 24 that rests on a desk or other support surface. The longitudinal pad 22 apparently would extend along the front of a keyboard 26 and outwardly from an edge thereof, such that the longitudinal pad 22 may be used in conjunction with a computer mouse 28. As is shown, the keyboard 26 and computer mouse 28 rest on the base 24.
Wrist rests such as that disclosed in Garcia et al. and similar devices have a number of disadvantages. For example, the longitudinal pad 22 does not alleviate the need for shoulder and arm movement during the course of moving the pointing device, especially toward and away from the user. Such movement is illustrated in FIGS. 2A and 2B. This forward and backward movement creates friction between the user's forearm and the wrist rest 20 which, combined with the pressure applied to the wrist area, irritates the wrist tissue and contributes to Carpal Tunnel Syndrome. Furthermore, movement of the arm and shoulder can work the shoulder and neck muscles to the point of aggravation. Also, the chronic repetitive lifting of the arm while using the computer mouse 28 and moving between the keyboard 26 and computer mouse 28 often causes fatigue and aching of the shoulder and neck muscles.
In addition to the disadvantages described above, prior art solutions such as the one suggested in Garcia et al. do not accommodate variations in the vertical positioning of the pointing device and wrist rest relative to the user. This problem is caused by the relative angles between the forearm, wrist, and the pointing device. In turn, the relative angles are affected by the heights of the rest 20 and pointing device 28. Suppose a wrist rest is configured for a normal work surface height as shown in FIG. 2A, but that the rest 20 and computer mouse 28 are moved to a lower position as shown in FIG. 2C, e.g., on the user's lap, or to a higher position as shown in FIG. 2D, e.g., to a higher section of a desk, or on top of a book or other desk clutter. The relationship between the arm, the wrist rest, and the pointing device will change as the wrist rest and pointing device are moved from the work surface. If the wrist rest and pointing device are positioned in a relatively low position, a wrist support that is too short will require the wrist to bend or flex upwardly. Additionally, in such a position the user's upper arm may be forced to lift off the rest in order to effectively use the pointing device, as is shown in FIG. 2C. Conversely, when the wrist rest 20 and pointing device 28 are used in a relatively high position, as shown in FIG. 2D, there is an arching of the wrist and arm, which is uncomfortable, applies more pressure to the wrist, and causes the wrist to bend.
Another disadvantage of prior art solutions such as that described for Garcia et al. is that use of the wrist rest is inconvenient when the keyboard/mouse is placed on the user's lap. Such rests are characteristically bulky and do not join the keyboard and pointing device in a way that is compact and stable on the user's lap. The advantages of placing the keyboard and pointing device on the user's lap are multifold, including workspace optimization and improved ergonomics. The workspace is optimized by eliminating the need for a desk to support the keyboard and pointing device, and by enabling the user to shift from one area to another within the workspace. The ergonomics are improved by enabling the arms to hang relaxed, the wrists to posture straight, the elbows and legs to bend 90.degree., and the feet to be positioned flat on the floor without the need for multiple ergonomic devices. The user only requires a chair of proper height, a computer screen placed at proper height, and a means of supporting the keyboard and pointing device on the lap.
In addition to the disadvantages described above, prior art solutions are not compact, portable and storable in a briefcase for mobile use with a portable computer. Furthermore, the wrist rest portions are not integrated into computer keyboards, portable computers, or computer pointing devices.
There is a need for a support that may be used with computer pointing devices that will minimize posture- and stress-related injuries, including those injuries stemming from shoulder movement and wrist extension/flexion, while still allowing quick target acquisition. It would be advantageous to have a rest that is positioned relatively close to the pointing device. Further, it would be advantageous if the support was configurable to allow it to be joined or integrated into a keyboard, a portable computer, or a pointing device. Integration of a rest with pointing devices will become increasingly important as the popularity of portable computers increases. Further desirable features of a support are compatibility with laptop use, ease of assembly/disassembly and storage, and portability.